<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        .ht{
            text-align: center;
            color: cadetblue;
            font-family: 幼圆;
        }
        .tab{
            width: 500px;
            border: 5px solid cadetblue;
            margin: 0px auto;
            border-radius: 5px;
            font-family: 幼圆;
        }
        .ltr td{
            border: 1px solid  powderblue;

        }
        .ipt{
            border: 0px;
            width: 50%;

        }
        .btn1{
            border: 2px solid powderblue;
            border-radius: 4px;
            width:60px;
            background-color: antiquewhite;

        }

        .msg {
            color: gold;
        }

        .buttonContainer{
            text-align: center;
        }
    </style>

    <script>
        function checkUserName() {
            // 实例化 一个 xmlHttpRequest
            var request = new XMLHttpRequest();
            var usernameInput = document.getElementById("usernameInput");
            var username = usernameInput.value;
            var usernameMsg = document.getElementById("usernameMsg");
            // 设置 xmlHttpRequest 对象的回调函数 readState 1 2 3 4
            request.onreadystatechange=function (){
                if (request.readyState === 4 && request.status === 200){
                   usernameMsg.innerText=request.responseText
                    console.log(request.responseText);
                }
            }

            // 设置发送请求的方式和请求的资源路径
            request.open("GET",'/user/checkUsernameUsed?username=' + username)
            // 发送请求
            request.send()
        }
    </script>

</head>
<body>
<h1 class="ht">欢迎使用日程管理系统</h1>
<h3 class="ht">请注册</h3>
<form method="post" action="/user/register" >
    <table class="tab" cellspacing="0px">
        <tr class="ltr">
            <td>请输入账号</td>
            <td>
                <input class="ipt" id="usernameInput" type="text" name="username" onblur="checkUserName()">
                <span id="usernameMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td>请输入密码</td>
            <td>
                <input class="ipt" id="userPwdInput" type="password" name="userPwd" >
                <span id="userPwdMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td>确认密码</td>
            <td>
                <input class="ipt" id="reUserPwdInput" type="password" >
                <span id="reUserPwdMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td colspan="2" class="buttonContainer">
                <input class="btn1" type="submit" value="注册">
                <input class="btn1" type="reset" value="重置">
                <button class="btn1"><a  href="/index.html">去登录</a></button>
            </td>
        </tr>
    </table>

</form>



</body>
</html>